Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS FOR ASCENDING AND DESCENDING STAIRS WITH A
WHEELCHAIR
Field of the Invention
[0001] This invention is in the field of devices for assisting the
disabled, and
relates primarily to assisting wheelchair-bound persons to ascend and descend
stairs.
Background of the Invention
[0002] With an aging population and a resulting increase in the relative
proportion
of persons having issues with mobility who require the use of a wheelchair,
there is a
need for devices that assist such persons to continue to live in their homes,
including
assisting them to navigate stairs.
[0003] Various devices are known for use in moving persons in wheelchairs
up
and down interior stairs. For example, US Patent No.4,345,669 (24 August 1982;
Wheelchair Lift; Noall), discloses such a device.
[0004] Such devices are not normally used to deal with external stairs.
Rather,
it is usual to retro-fit a permanent or semi-permanent ramp to enable the
wheelchair
user to bypass the stairs. However, such fixed ramps must have a gentle slope
and
thus require considerable space and material. A maximum slope of 1:12 is
recommend for exterior wheelchair ramps. Thus, each one-foot rise requires
twelve
feet of run in order to provide the desired maximum slope. In many situations,
there is
inadequate room for a ramp with the desired maximum slope.
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Summary of the Invention
[0005] In
one aspect, the present invention provides a device that permits a
wheelchair to traverse stairs. A carriage supporting the wheelchair is housed
in an
inclined ways assembly and moves by means of a rotated coil rod supported in
the
ways and traveling nuts fixed to the carriage; a debarkation ramp hinged to
the carriage
bridges the distance and elevation difference between the carriage and the
desired
landing point.
[0006] In
another aspect, the present invention provides an apparatus for use in
transporting a wheelchair up or down a set of stairs, the apparatus including:
a
longitudinally extending ways assembly, having a lower end and an upper end; a
wheelchair platform supported by the ways assembly; a motive arrangement for
selectively moving the wheelchair platform along the length of the ways
assembly
between a top position in which a wheelchair may move substantially directly
between
the wheelchair platform and the top of the stairs and a bottom position; and a
ramp
having a proximal end and a distal end, the proximal end hingedly attached to
the
wheelchair platform and the distal end having a ground engagement feature,
wherein
contact between the ground engagement feature and the ground as the wheelchair
platform moves towards the bottom position, causes the ramp to pivot away from
the
ways assembly so as to provide a wheelchair path of travel between the
wheelchair
platform and the ground when the wheelchair platform is in the bottom
position, and
movement of the wheelchair platform towards the top position permits the ramp
to pivot
towards the ways assembly.
[0007] The
motive arrangement may include a threaded rod rotatably mounted
to the ways assembly and a primary traveling nut threadedly engaging the
threaded rod
attached to a traveling member, wherein rotation of the threaded rod causes
the
traveling member to move along the length of the ways assembly.
[0008] The
wheelchair platform may include a carriage frame having a base
affixed to the traveling member and extending along the length of the ways
assembly
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so as to provide support for a wheelchair. The apparatus may also include a
secondary
nut threadedly engaged with the threaded rod and affixed to the carriage frame
in a
spaced apart relationship from the primary traveling nut.
[0009]
The ways assembly may include two opposed side walls, wherein each
side wall has a longitudinally extending channel; and wherein the wheelchair
platform
includes: a plate having a proximal edge and a distal edge, and attached in
the vicinity
of the proximal edge to the traveling member and hingedly attached at the
distal edge
to the ramp; and two rollers, each roller engaging a respective channel,
wherein the
wheelchair platform is supported by the traveling member and the channels. The
position of the rollers may be adjustable.
[0010]
The apparatus may include a motor attached to the threaded rod and
configured for selectively reversibly rotating the threaded rod.
[0011]
The apparatus may include a removeable adapter for connecting a hand-
operated reversible power drill to an end of the threaded rod.
[0012]
The apparatus may include a manual implement for removably
connecting to an end of the threaded rod for manually rotating the threaded
rod. The
manual implement may be a hand wheel.
[0013]
The ground engagement feature may include two wheels spaced apart
one from the other. The ramp may have side rails.
= [0014] The ramp may be hingedly attached to the wheelchair
platform by a hinge
having a reversibly retractable hinge pin whereby a user may detach the ramp
from the
wheelchair platform by manual withdrawal of the hinge pin and may attach the
ramp to
the wheelchair platform by manual insertion of the hinge pin.
[0015]
The apparatus may include means for stabilizing the apparatus at a
desired position relative to the stairs. The stabilizing means may include a
stair foot for
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fixing at a desired position interposed between the ways assembly and a tread
of the
stairs. The stabilizing means may include a ground shoe located in the
vicinity of the
lower end of the ways assembly for frictionally engaging the ground.
Summary of the Drawings
[0016]
Figure 1 is a side elevation view of a wheelchair-lift assembly
embodiment of the present invention, referred to herein at times as a carriage
embodiment, shown installed on a set of stairs, with the carriage at the top
position,
being the position suitable for accepting or releasing a wheelchair at the top
of the set
of stairs.
[0017]
Figure 2 is a side elevation partially cut-away view of the carriage-type
embodiment shown in Figure 1, shown with the carriage at the top position.
[0018]
Figure 3 is a side elevation view of the carriage-type embodiment shown
in Figure 1, shown with the carriage at the bottom position, being the
position suitable
for accepting a wheelchair from, or releasing a wheelchair to, the surface
adjacent the
lower end of the set of stairs.
[0019]
Figure 4 is a partially cut-away perspective view of the carriage and ways
assembly of the carriage-type embodiment shown in Figure 1.
[0020]
Figure 5 is a perspective view from the proximal end of the ramp of the
carriage-type embodiment of Figure 1, with the ramp shown detached from the
carriage.
[0021]
Figure 6 is a perspective view from the distal end of the ramp of the
carriage-type embodiment of Figure 1, with the ramp shown detached from the
carriage.
[0022]
Figure 7A is a partially sectional isolation view from perpendicular to the
general plane defined by the ways assembly, of the upper end of the ways
assembly
of the carriage-type embodiment shown in Figure 1.
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[0023] Figure 7B is a partially sectional isolation view from
perpendicular to the
general plane defined by the ways assembly, showing features of the interior
of the
carriage, of the carriage-type embodiment shown in Figure 1.
[0024] Figure 7C is a partially sectional isolation view from
perpendicular to the
general plane defined by the ways assembly, of the lower end of the ways
assembly of
the carriage-type embodiment shown in Figure 1.
[0025] Figure 8 is a perspective view of another embodiment of the
present
invention, referred to herein at times as a side-channel embodiment, shown
installed
on a set of stairs, with the plate at the top position, being the position
suitable for
receiving a wheelchair from, or delivering a wheelchair to, the top of the set
of stairs.
[0026] Figure 9 is a side elevation simplified view of a side-channel
embodiment
shown with the plate in the top position.
[0027] Figure 10 is a side elevation simplified cutaway view of a side-
channel
embodiment shown with the plate an intermediate position.
[0028] Figure 11 is a side elevation simplified view of a side-channel
embodiment
shown with the plate in the bottom position being the position suitable for
receiving a
wheelchair from, or delivering a wheelchair to, the surface adjacent the lower
end of the
set of stairs.
[0029] Figure 12 is a top plan view of a side-channel embodiment shown in
Figure 8 in the top position.
[0030] Figure 13 is a top plan simplified view of a side-channel
embodiment in
the bottom position .
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[0031] Figure 14 is a perspective isolation view showing details of the
plate, plate
hinge and adjacent features of a side-channel embodiment.
[0032] Figure 15 is a bottom plan simplified view of the plate, axle and
rollers of
a side-channel embodiment.
[0033] Figure 16 is a side elevation simplified cutaway view of an
embodiment
having a drive motor.
[0034] Figure 17 is a side elevation simplified cutaway view of an
embodiment
showing a socket extension and power drill aligned for use in moving the
plate.
[0035] Figure 18 is a side elevation simplified cutaway view of an
embodiment
showing a socket extension and hand wheel in position for use in moving the
plate.
[0036] Figure 19 is a perspective view of a side-channel embodiment
having
side rails on the debarkation ramp shown with the plate in the bottom
position.
[0037] Figure 20 is a top plan view of the embodiment shown in Figure 19
showing the plate in the bottom position.
[0038] Figure 21 is a side elevation view of the carriage-type embodiment
shown
in use with a vehicle.
Detailed Description with Reference to the Drawings
[0039] As shown in the drawings, embodiments of the present invention
include
a carriage-type embodiment 120. The carriage-type embodiment 120 has a ways
assembly 122, carriage 124 and debarkation ramp 126.
[0040] The ways assembly 122 includes a ways 130, rotatable coil rod 132
(i.e.,
a threaded rod), and associated with each end of the coil rod 132, a thrust
bearing 134
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and engaging nut 136. As shown in Figures 1 - 3, a socket extension 137 may be
removeably fitted to the upper engaging nut 136 for rotating he coil rod 132
(described
in further detail below).
[00411 The
ways assembly 122 includes a stair foot 138 and a ground foot 139.
The stair foot 138 and the ground foot 139 are preferably made from a material
having
a relatively high-friction surface so as to frictionally engage the stairs and
ground
respectively. The position of the stair foot 138 along the length of the ways
assembly
122 is preferably adjustable by the user/installer so as to accommodate
differences in
step height and stair pitch.
[0042] The
carriage 124 includes a carriage frame 140, a carriage frame platform
142 (for supporting a wheelchair) and two traveling nuts 144. The traveling
nuts 144
are fixed relative to the carriage frame 140 and the coil rod 132 is threaded
through
both traveling nuts 144 such that rotation of the coil rod 132 causes the
carriage 124
to move along the length of the coil rod 132.
[0043] The
ramp 126 has at its proximal end a piano hinge 150 that it in use is
affixed to the carriage 124 so as to provide hinged relative movement as
between the
carriage 124 and ramp 126. The ramp 126 has at its distal end wheels 152
(possibly
casters or alternatively, low-friction sliders) for traversing the surface
adjacent the
bottom of the stairs when the carriage-type embodiment 120 is in use. The
wheels 152
permit the distal end of the ramp 126 to accommodate uneven and variable
terrain that
may be a permanent feature or may result from transitory ice or snow.
[0044]
Preferably, the ramp 126 has side rails154 to assist in guiding wheelchair
movement along the ramp 126. In the figures, some representations of the ramp
126
have side rails 154 and others do not.
[0045] As
shown in the drawings, the carriage-type embodiment 120 may be
installed on a set of stairs 160. As shown in Figures 1 and 2, in some
installations, it
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may be desirable or necessary to include a bridge 170 to span the gap between
the
landing at the top of the stairs and the platform 142.
[0046] When installed, the carriage 124 is moveable through rotation of
the coil
rod 132 between a top position, being the position suitable for accepting or
releasing
a wheelchair at the top of the set of stairs, in which the ramp 126
essentially overlies
the ways assembly 122, and a bottom position, in which the ramp 126 projects
from the
carriage 124 so as to be in a position suitable for traverse by a wheelchair
between the
surface adjacent the lower end of the set of stairs 160 and the carriage frame
platform
142.
[0047] In use, with the carriage 124 in the bottom position, the distal
end of the
ramp 126 may also be positioned elsewhere than on the surface adjacent the
bottom
of the stairs 160. As shown in Figure 21, the distal end of the ramp 126 may
be
positioned in the entry way of a vehicle 180 so as to facilitate direct
wheelchair travel
between carriage frame platform 142 and the vehicle 180. This positioning of
the ramp
126 may be obtained by pre-positioning the vehicle 180 and raising the distal
end of
the ramp 126 as the carriage 124 is moved towards the bottom position, either
manually
or by means of a track or tracks for guiding the distal end of the ramp 126
into the
desired position. Alternatively, the ramp 126 may be configured to be
extendible such
that the ramp 126 may be lifted and extended to bring the distal end of the
ramp 126
into engagement with the vehicle entryway with the carriage 124 in the bottom
position.
[0048] In many situations, the carriage-type embodiment 120 may be
installed
without being fastened to the stairs. The carriage-type embodiment 120 clears
the
steps from the top tread to the lower landing without any fastening.
[0049] The carriage-type embodiment 120 may be configured to accommodate
different stair pitches by configuring the carriage 124 such that the angle of
the carriage
frame platform 142 relative to the carriage frame 140 may be adjusted.
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[0050] A side-channel embodiment 200 is shown in Figure 8 and following
figures. The side-channel embodiment 200 has a side-channel ways assembly 212,
a plate assembly 214 and a debarkation ramp 126.
[0051] The side-channel ways assembly 212 includes a ways 130, rotatable
coil
rod 132, and associated with each end of the coil rod 132, a thrust bearing
134 and
engaging nut 136. Attached to each side of the ways 130 is a sidewall 220.
each
sidewall 220 has a channel 222 extending along the length of the sidewall 220.
The
side-channel ways assembly 212 preferably includes a stair foot 138 and ground
foot
139.
[0052] The plate assembly 214 includes a traveling member 230 having a
traveling nut 144 affixed thereto and with the traveling nut 144 in threaded
engagement
with the coil rod 132. Attached to the traveling member 230, there is a plate
232.
Attached to the plate 232 there is a roller assembly 234 comprising two
rollers 236 and
a roller axle 238. As shown in Figure 15 the rorer axle 238 is affixed to the
bottom of
the plate 232 by way of U-fasteners 240 installed in roller mounting holes
242. There
are multiple roller mounting holes 242 and thus the position of the roller
assembly 234
may be adjusted by installing the U-fasteners 240 in the desired roller
mounting holes
242 (for example, so as to accommodate differences in pitch).
[0053] Each roller 236 engages the interor of, and is thereby supported
by, a
respective channel 222.
[0054] The ramp 126 is attached to the distal edge of the plate 232 by
way of a
pin hinge 250. The pin 252 of the pin hinge 250 may be removed and reinserted,
thus
permitting easy separation of the plate 232 and ramp 126, such as for
maintenance or
adjustment of the side-channel embodiment 200.
[0055] As compared to the carriage-type embodiment 120, the side-channel
embodiment 200 tends to provide a less-steep s'ope when the ramp 126 is in use
as
a wheelchair pathway, in that, when the plate assembly 214 is in the bottom
position,
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the wheelchair is closer to the ground than when the carriage 124 is in the
bottom
position.
[0056] As shown in Figure 16, a drive motor 260 may be mounted to the
ways
130 in permanent drive engagement with the coil rod 132. A drive motor 260 may
be
controlled by a mounted switch (not shown) if control is to be by a person
assisting a
person in a wheelchair, or by a remote radio device (not shown), if control is
to be by
a person in a wheelchair or by a person assisting a person in a wheelchair.
Preferably,
an embodiment with a drive motor 260 would have automatic cut-off switches
(not
shown) to stop the drive motor 260 once the top position or bottom position
(as the case
may be) has been achieved.
[0057] As shown in Figure 17, the socket extension 137 may be used with a
conventional two-direction power drill 262 to rotate the coil rod 132 as
required.
Alternatively or as a fall back in the event of a power failure, as shown in
Figure 18 the
socket extension 137 may be used with a hand wheel 264 to rotate the coil rod
132 as
required.
[0058] Various forms of lead screw assemblies and nut combinations (i.e.,
coil
rods and traveling nuts) are known and a designer would be able to readily
select and
obtain a suitable off-the-shelf combination.
